Fluidized solids reactor with refractory lining

ABSTRACT

FLUIDIZED SOLIDS REACTOR, E.G., A FLUID BED CHLORINATOR HAVING A REFRACTORY BRICK LINING THAT UTILIZES FINELY DIVIDED REFRACTORY METAL OXIDE POWDER TO FILL THE JOINTS BETWEEN BRICKS IS DESCRIBED. OPTIONALLY, THE HIDDEN FACES OF THE BRICK HAVE A COATING OF THE REFRACTORY METAL OXIDE POWDER.

nited States Patent Office 3,813,225 FLUIDIZED SOLIDS REACTOR WITHREFRACTORY LINING Richard S. Cook, New Martinsville, W. Va., assignor toPPG Industries, Inc., Pittsburgh, Pa.

No Drawing. Original application Mar. 10, 1969, Ser. No. 805,822, nowabandoned. Divided and this application Sept. 20, 1971, Ser. No. 182,138

Int. Cl. B011 1/20 U.S. Cl. 23-284 Claims ABSTRACT OF THE DISCLOSUREFluidized solids reactor, e.g., a fluid bed chlorinator having arefractory brick lining that utilizes finely-divided refractory metaloxide powder to fill the joints between bricks is described. Optionally,the hidden faces of the brick have a coating of the refractory metaloxide powder.

This is a division of application Ser. No. 805,822, filed Mar. 10, 1969,now abandoned.

BACKGROUND OF THE INVENTION Refractory brick is used commonly to linethe interior surfaces of vessels within which high temperatures aregenerated and/or within which an atmosphere corrosive to metals isfound. The type of refractory brick employed in such vessels varies withthe function of the vessel. For example, refractory brick used forceramic kilns and furnaces differs from that used in blast furnaces andfluidized-solids reactors. In the last mentioned vessels, refractorybrick typically is resistant to both high temperatures and a corrosiveor erosive atmosphere resulting from chemical reaction and movement ofmaterial within the vessel. A typical example of the latter type vesselis a fluidized-solids chlorination reactor wherein metallic chloridesare produced by treatment of a particulate ore with gaseous chlorine atelevated temperatures.

Conventionally, the refractory lining of a reaction vessel is fabricatedfrom several courses (rows) of refactory brick bonded together with abonding mortar compatible with the brick. Typically, the mortar isprepared with water. When the refractory lining is dried, most of thewater in the mortar is removed. However, a small quantity of waterremains in the mortar either as water of hydration, or as chemicallyuncombined water. In vessels wherein a chlorination reaction isconducted, the presence of such water produces a deleterious effect onthe refractory brick and metal shell. For example, in such achlorination vessel, hot gaseous chlorine will combine with water toform hydrochloric acid. The hydrochloric acid attacks the refractorybrick and metal shell causing severe deterioration of these materials,particularly within the inner courses of brick comprising the vessellining. Such deterioration can cause premature shutdown of the processconducted within the vessel and expensive replacement of the refractorybrick lining.

It has been proposed to protect refractory linings by coating thesurface of the refractory brick exposed to the interior of the vesselcontaining the lining with various 3,813,225 Patented May 28, 1974fractory brick to very close tolerances in order to provide a liningwhich is both structurally sound and impervious to the outsideatmosphere and the contents, e.g., gases, solids and liquids, within thevessel. The latter requirement prevents the egress of the contents ofthe vessel, especially gas charged to or generated within the vessel, tothe shell of the vessel and to the atmosphere. Use of the aforesaid dryassembly of refractory brick has not proven to be entirely successful.In chlorination vessels, for example, gaseous chlorine charged to thevessel seeps through the interstices between the refractory brick and islost to a recovery or waste system. In commercial fluidized bedchlorinators, such loss can be substantial and not only increaseschlorine recovery costs but also poses a potential health hazard.

BRIEF SUMMARY OF THE INVENTION It has now been discovered that the lifeof refractory brick can be prolonged by applying finely-dividedrefractory metal oxide having a melting point greater than the operatingtemperature of the vessel to the surfaces of the brick in an amountsufiicient to fill substantially all of the surface pores of the brick.In a preferred embodiment, a superficial coating of the metal oxide isalso applied to one or more hidden faces of the brick. It has furtherbeen found that a substantially impermeable assembly of refractory brickcan be fabricated without a conventional bonding mortar, i.e., dry, byfilling the joints between the refractory brick, i.e., the spacebetween, adjacent, or abutting brick surfaces, with said refractorymetal oxide powder.

DETAILED DESCRIPTION The present invention relates to a method ofprolonging the life of refractory brick, to the brick produced by theuse of said method, and to a dry assembly of such brick. Thehereindescribed method and refractory brick are particularly applicableto chlorination vessels and are especially useful in fluidized bedchlorinators. Although the present invention will be discussedhereinafter with respect to such chlorination vessels, it should beunderstood that the present invention is applicable to any refractorybrick lined vessel wherein the atmosphere within the vessel duringoperation of the process conducted therein causes deterioration of therefractory brick lining.

Conventionally, chlorination vessels are constructed of a metal, e.g.,steel, cylindrical shell lined with several courses (rows) of refractorybrick. Subdivided ore or concentrate, usually with a carbonaceousreducing agent, is fed into the vessel through the top or through a sideport and chlorine is fed into the vessel through the bottom. Thechlorine entry and ore feeds can be arranged to produce a fluidized bedin which the ore and carbonaceous particles are suspended and agitatedin the upwardly moving chlorine gas flow during the chlorinationreaction. Chlorination is conducted at elevated temperatures, often inthe range of from 1500 F. to 2000" F. Metallic chloride is produced as avapor together with gaseous byproducts and these gases are withdrawnfrom the vessel and the metallic chloride products separated, condensedand purified for appropriate use. A typical example of theaforementioned process is the chlorination of a titaniferous ore, e.g.,rutile TiO in the presence of coke to produce titanium tetrachloride.Titanium tetrachloride is a well-known commercial product and is usefulin the production of titanium metal and titanium oxide pigments.

In a typical fluidized bed chlorinator for the chlorination oftitaniferous ore, about 30 to 50 percent of the height of thechlorinator is occupied by the fluid bed and is usually termed theworking or fluid bed section. The remaining portion of the chlorinatoris usually referred to 3 as the disengaging section. In the workingsection of the chlorinator, the chlorine, titaniferous ore and carbonundergo chemical reaction to form, principally, titanium tetrachloride,carbon dioxide and carbon monoxide. Other metal halides, e.g., ironchlorides, depending on the chemical composition of the ore, are alsoformed. The portion of the working section where chlorination occurs,i.e., where formation of the metal chlorides principally takes place, isthe oxidation section, i.e., the atmosphere is oxidative in character.The remaining portion of the chlorinator principally has a reducingatmosphere due to the presence of substantial quantities of carbondioxide and carbon monoxide, and, the substantial absence of chlorine.

The refractory brick lining of a fluid bed chlorinator is subjected tocorrosive attack by the hot gases within the chlorination vessel, e.g.,chlorine, carbon monoxide and carbon dioxide, and also to erosion causedby the action of the bed against the refractory brick. Typically,adjacent refractory brick are bonded together with a bonding mortarwhich even after drying contains residual water. The hot chlorine and/ortitanium tetrachloride within the vessel combines with residual water inthe mortar to form hydrochloric acid. At the temperatures of operation,hydrochloric acid is extremely corrosive to the refractory brick. Itattacks the mortar and the brick causing a condition known as corrosion.Often, the corrosion is more severe on the internal courses of brickthan at the surface of the brick exposed to the interior of thechlorination vessel. If corrosion is severe enough, the hydrochloricacid can also reach and attack the steel shell of the chlorinator.

It is, therefore, necessary that refractory linings of chlorinationvessels and other vessels reflecting similar operating conditions beboth corrosion and erosion resistant. Further, the refractory liningmust provide sufficient thermal insulation so that the exothermic heatof reaction or added heat is conserved to sustain substantially uniformoperating temperatures for extended periods of steady state operation.Typically, therefore, chlorination vessel refractory linings arefabricated with one or more layers of insulating refractory brickadjacent to the steel shell and one or more inner layers of refractorybrick adjacent to the insulating refractory brick and the workinginterior of the chlorination vessel.

Because of the water content of the bonding mortar utilized to cementrefractory brick together, typically about 14 weight percent, and thecorrosion difficulties resulting therefrom, it has been suggested thatrefractory brick be laid-up dry, i.e., without using any mortar.However, such fabrication requires machining of refractory brick to veryclose tolerances (a costly procedure); and, even then, does not succeedin providing an over-all interior surface that is substantiallyimpervious to gas.

In accordance with the present invention, at least one surface ofrefractory brick is treated with a refractory metal oxide so thatsubstantially all of the exposed surface pores or voids are filled withthe metal oxide. In addition, and preferably, a superficial coating ofthe refractory metal oxide is placed on the surface of the brick.Preferably, the hidden faces of the refractory brick, i.e., faces notexposed to the interior of the chlorination vessel, are treated and/orcoated with refractory metal oxide. Refractory brick treated, asdescribed, can be dry assembled and the joints between bricks filled(grouted) with refractory metal oxide to produce a substantially gasimpervious refractory lining.

It has been found that an assembly of refractory brick, as heretoforedescribed, retards the seepage of gas from the interior of thechlorination vessel through the interstices between the refractory brickand the brick per se, and substantially prevents deterioration of theinternal courses of refractory brick. The manner in which deteriorationis prevented is not exactly known; however, it is presumed that thepermeability of the brick is reduced sufficiently to prevent carbonmonoxide and chlorine gas from reaching the internal courses of brick.

The present invention is applicable to newly constructed chlorinationvessels, as well as existing chlorination vessels. In the latter case,as a course of refractory brick, or a portion thereof, is replaced,replacement is made in accordance with the hereindescribed method. Forexample, if the course of refractory brick exposed to the interior ofthe chlorination vessel, i.e., the working course, is to be replaced,refractory metal oxide can be applied to the exposed face of theabutting course of brick, as well as to one or more hidden faces of therefractory brick being replaced. Once the brick to be replaced is inposition, any unfilled joints between the brick can be filled with therefractory metal oxide. The brick face exposed to the interior of thevessel is usually not covered with a coating of the refractory metaloxide for the reason that the metal oxide placed on this face is usuallyremoved by erosion or chemical combination from contact with thecontents of the vessel, e.g., the fluid bed and hot reacting gases. Inaddition, scale typically builds up on the hot face of the brickcomprising the working course after a period of operation. However, ifdesired, the exposed surface voids of this face can be filled with themetal oxide to aid in reducing the porosity of the brick.

In like manner, should the working course of refractory brick, as wellas several inner courses of brick, or any portion thereof requirereplacement, each refractory brick replacement can be treated with therefractory metal oxide in the manner described herein as it is replacedin the refractory wall. When an inner course of refractory brick isreplaced, it is preferred that all of its faces be treated with therefractory metal oxide.

In fabricating complete refractory linings for either a newlyconstructed chlorination vessel or a reconstructed chlorination vesselin accordance with the present invention, various techniques can beused. Exemplary of some techniques that can be used, alone or in anycombination are: (1) constructing an inner row of brick; grouting theinterstices between the brick with metal oxide; and, applying a surfacecoating of metal oxide to the remaining exposed faces, (2) constructingan inner row of brick using refractory metal oxide on abutting surfacesinstead of the conventional bonding mortar; and, applying a surfacecoating of metal oxide to the remaining exposed faces, (3) treating eachrefractory brick by filling the exposed pores or voids on each face withmetal oxide and/or applying a superficial coating of metal oxide to eachface; constructing an inner row of brick with said treated brick;grouting the interstices between the brick with metal oxide; andapplying additional metal oxide to the remaining exposed faces in a thinlayer to insure that all brick surfaces are covered, and (4) coating themetal shell with metal oxide to fill any gaps that occur between theshell andthe first row of brick and then construct the refractory wallusing any one or more of the preceding three techniques.

Whichever technique is used to construct an inner row of refractorybrick, the technique is repeated on subsequent rows of brick until thelast row or working course of brick is reached. The exact number of rowsof brick will vary with the particular reaction vessel and, therefore,the number of bricks and rows of brick treated in accordance with thepresent method does not represent a critical feature of the presentinvention. As indicated above, the working face of brick is usually nottreated with a superficial layer of metal oxide because such layer isquickly removed by the reactor environment.

As used herein, the term refractory brick is intended to mean andinclude all types of bricks fabricated from non-metallic materials usedin the construction or lining of furnaces or other vessels operated athigh temperatures and/or within which an atmosphere corrosive to metalsis found. Exemplary of the type of bricks contemplated are fire-clay,high alumina, silica, silicon-carbide, zircon and basic, e.g.,magnesite, chrome, magnesite-chrome, chrome-magnesite, and forsterite.The compositions of each of the aforesaid types of brick vary withineach class and depend on the ultimate use to which the brick is to beput. Typical compositions of each of the grades of the aforementionedbrick and their methods of preparation are known in the art and can beobtained by reference to any standard refractory text. Such a text isModem Refractory Practice, 4th Edition, copyright 1961 by theHarbison-Walker Refractories Company. The portions of that text relatingto the compositions, e.g., pp. 134, 135, 291 and 292, and methods ofpreparation of said refractory brick are incorporated herein byreference.

Refractory bricks are fabricated in a variety of shapes and sizes. Forexample, the various shapes include: rectangular sizes (such asstraights, soaps and splits); tapered sizes having only plane surfaces(such as arch, wedge, and key brick); neck skew, feather edge, and jambbrick; and tapered sizes having two curved surfaces (circle brick,cupola blocks and rotary kiln blocks). A discussion and representationof such shapes and sizes can be found on pages 477-479 of the aforesaidtext, Modern Refractory Practice. Most of the standard refractory brickshapes have six sides or faces. Jamb brick has five sides, one sidebeing curved, thereby occupying two sides of a normally rectangularbrick.

In accordance with one embodiment of the present method, an assembly ofrefractory bricks are dry assembled and the interstices or jointsbetween the bricks filled with refractory metal oxide. In anotherembodiment, at least one face, advantageously the hot face, of therefractory brick is treated with refractory metal oxide in an amountsuflicient to fill substantially all of the exposed surface pores of thebrick and thereby reduce its porosity or permeability. Preferably, atleast (n-l) faces of the brick are thus treated. The letter n in theexpression (n-l) represents the total number of faces (sides) possessedby the brick. Typically, n will be 5 or 6. More preferably, all of thefaces of the brick are treated with metal oxide. In a still furtherembodiment, a superficial coating of metal oxide is placed on at leastone hidden face of the refractory brick, typically the hot face, and,preferably, such a coating is placed on all hidden brick faces.

The refractory metal oxide utilized to treat the refractory brick inaccordance with the method of the present invention is any refractorymetal oxide having a melting point greater than the operatingtemperature of the vessel. Preferably, the refractory metal oxide willalso have some chemical resistance to the atmosphere, e.g., reducing,oxidative, basic and acidic, to which it is exposed-and be compatiblewith the refractory brick with which it is used. For example, chemicalresistance should be suflicient to permit the operation of the processwithin the vessel containing the refractory lining for a reasonablelength of time, i.e., until a scheduled shutdown or for a normal processrun. The exact length of time will vary from reactor to reactor andprocess to process. In the case of metal oxide used for inner courses ofbrick, chemical resistance may not be required since the metal oxide maynever be physically exposed to the atmosphere within the vessel.

The operating temperature of the vessel is intended to mean the highesttemperature reached within the vessel, e.g., a fluid bed chlorinator,during continuous operation of the process conducted, e.g.,chlorination, in the vessel. Absent hot spots, this temperautre willusually be the highest temperature within the vessel under steady stateoperating conditions. In thecase of a fluidized bed chlorination vesselutilized for the chlorination of titaniferous ores, the operatingtemperature of the vessel is typically greater than 1600 F., and usuallyless than 1900 F.

'Exemplary of refractory metal oxides that have melting pointssufficiently high to be considered useful in the 6 method of the presentinvention include: aluminum oxide (A1 0 barium oxide (BaO), berylliumoxide (BeO), calcium oxide (CaO), cerium oxide (Ce0 chromic oxide (Cr Ocobalt oxide (C00) gallium oxide (GagO' hafnium oxide (HfO lanthanumoxide (1.3 0 magnesium oxide (MgO), manganese oxide (MnO), nickel oxidepresent invention include: aluminum silicate (mullite- 3lA1203'2Si02),aluminum titanate (Al O -TiO or A1 0 2TiO barium aluminate (BaO-AI O orBaO -6AI O barium silicate (ZBaO-SiO barium zirconate (BaO- ZrO-beryllium aluminate (BeO-Al o beryllium silicate (BeO-Si0 or 2BeO-SiOz), berryllium titanate (3BeO-TiO beryllium zirconate (3BeO-2ZrOcalcium chromate (CaO-CrO calcium chromite (CaO-Cr O calcium phosphate(3CaO-P O5L calcium silicate (3Ca0- SiO or 2CaO-SiO calcium siliconphosphate (SCaO- SiO -P O5), calcium titanate (CaO-TiO or 2CaO-Ti0 orBCaO-TiO calcium zirconate (CaO-ZrO cobalt aluminate (COO-A1 0 magnesiumaluminate (MgO- A1 0 magnesium chromite '(MgO-Cr 0 magnesium ferrite(MgO-Fe O magnesium lanthanate (MgO- 143.203), magnesium silicate(2MgO-SiO magnesium titanate (ZMgO-TiO magnesium zirconate (MgO- ZrOmagnesium zirconium silicate (MgO-ZrO -SiO nickel aluminate (NiO-Al Opotassium aluminum silicate (K O-Al O -2SiO strontium aluminate (SrO- A10 strontium phosphate (3SrO-P2O5), strontium zirconate (SrO-ZrO- thoriumzirconate (ThO -ZrO zinc aluminate (ZnO-Al O zinc zirconium silicate(ZnO-ZrO -Si0 and zirconium silicate (zircon-ZrO SiO Economicallypreferred refractory metal oxides include: silicon oxide (SiO titaniumoxide (TiO zirconium oxide (ZrO magnesium oxide (MgO), aluminum oxide(A1 03), mullite (3Al O' -2SiO- and zircon (Zr0 SiO More than one metaloxide can be used in a refractory assembly, e.g., aluminum oxide orzirconium oxide can be used for one course of brick or in a portion ofone course of brick and silicon oxide or titanium oxide for anothercourse of brick or in another portion of the same course.

Selection of a particular refractory metal oxide, which includes complexmetal oxides, depends on the conditions prevailing within the vessel,e.g., temperature, pressure and chemical environment. Such conditionsaffect the relative stability of the metal oxide. Price is also aconsideration. By matching the environment existing at a particularcourse of brick, or portion thereof, with the properties of the metaloxide, a suitable refractory metal oxide can be selected. For example,if an oxidizing atmosphere is present in the vessel or a portionthereof, a metal oxide resistant to oxidation at the operatingtemperatures and chemical environment is used. Similarly, if a reducingatmosphere is present in the vessel or a portion thereof, a metal oxideresistant to reduction at the operating temperatures and chemicalenvironment is used. If both oxidizing and reducing atmospheres arepresent in different portions of the vessel, two metal oxides can beused, or one metal oxide resistant to both oxidation and reduction canbe used. Finally, where the only consideration in selecting a metaloxide is resistance to temperature, any refractory metal oxide having amelting point above the operating temperature of the vessel can be used.In this case, price and availability will be the important factorsconsidered.

The refractory metal oxide should be finely-divided and substantiallydry. Pigmentary metal oxides are especially suitable. For example,pigmentary titanium dioxide either uncoated or coated with hydrous metaloxides can be used. Typically, the ultimate particle size of pigmentarytitanium dioxide ranges from about .2 to about .5 microns. The actualsize of the refractory metal oxide used can vary; however, the degree ofsub-division of the metal oxide should be sufficient, i.e., the particlesize should be sufficiently small, so that the metal oxide will fill theexposed surface pores in the refractory brick. The apparent porosity ofrefractory brick ranges from about 8 to about 33 percent depending onthe particular grade of refractory. Apparent porosity is the ratio ofthe volume of the pores or voids in a body to the total volume and isbased upon the open pore-volume only (as distinguished from the totalpore-volume). Thus, by reducing the apparent porosity of the brick, itspermeability is also reduced. Since the refractory metal oxide isapplied to the refractory brick as a dry powder, the refractory metaloxide does not penetrate the brick to any significant depth. The exactdepth will depend to a great extent on the porosity of the brick andwill vary across the brick. In accordance with the present method, it iscontemplated that the exposed surface pores and/or voids of therefractory brick be filled with the metal oxide to depths obtained byapplication of the metal oxide to the surface with sufficient pressureto fill the pores and retain the metal oxide therein. Depths of ,4 inchor less, e.g., inch, can be obtained depending on the porosity of thebrick, and the manner of application.

The refractory metal oxide is applied to the refractory brick as a drypowder. By dry is meant that the moisture content of the metal oxide issufiiciently low so that the metal oxide retains essentially theproperties of a free flowing powder, i.e., the particles of metal oxidedo not cohere or stick to each other to any substantial degree. Somerefractory metal oxides when exposed to the air will adsorb water ofhydration and it is not intended to exclude refractory metal oxide inthat state provided, however, that the level of adsorbed water does notreach the aforementioned level. Pigmentary titanium dioxide, forexample, coheres, at mositure levels of about 0.5 weight percent.Therefore, a moisture content of less than 0.5 weight percent, e.g.,about 0.1 weight percent, is necessary to provide a dry" titaniumdioxide.

The refractory metal oxide can be applied to the refractory brick by anyconvenient method and at any convenient temperature, i.e., ambienttemperature. For example, the metal oxide can be applied manually to thesurface of the brick and the excess brushed off. Similarly, the metaloxide can be applied by spraying the metal oxide powder onto the brickwith any suitable air gun. It can be applied to the brick before orafter a course of brick is constructed. In the last mentionedembodiment, only one of the blind surfaces of the brick will be treated.When spraying is used to apply the refractory metal oxide, it isconvenient to add materials to the oxide that make it more free flowing.For example, the addition of from 3 to 5 weight percent silicon oxide(SiO to titanium oxide (TiO- produces a more free flowing titaniumoxide.

As used herein, the term hidden face or hidden surface is intended tomean and include all faces of the refractory brick not visible to thehuman eye when incorporated into a course (row) of brick or refractorylining. In the case of an inner course of brick, all faces of such brickare considered hidden when the completed refractory lining is viewed. Inthe case of brick exposed to the very interior of the vessel, all butthe exposed face are considered hidden faces.

The term hot face is intended to mean the face of a particular brick orsingle row of bricks having a common planar surface that is closest tothe interior of the vessel, i.e., where the process being conducted,e.g., chlorination, takes place. The term cold face is intended to meanthe face of a particular brick or single row of bricks having a commonplanar surface that is opposite to the hot face. Thus, each brick willhave a hot face and a cold face. Typically, the cold face will beadjacent to the hot face of an abutting brick in the same horizontalplane.

The practice of the present method allows for flexibility in treatingrefractory brick. For example, the surface of the brick can be treatedwith refractory metal oxide so as to fill substantially all the exposedpores of the brick surface. Any excess remaining on the surface can beeasily removed by lightly brushing the surface of the brick.Alternatively, a superficial coating of metal oxide can be applied to orleft on the surface of the brick. Such superficial coating willtypically vary from about 0.5 to about 10 mills in thickness.Thicknesses greater than 10 mills, i.e., up to inch or A inch, can beutilized; however, if the coating is too thick, it will flake 0E andresult in a non-uniform surface against which the next abutting courseof brick rests. Further, the coatings applied to the various hiddensurfaces of the brick need not be uniform, i.e., only an intimateprotective coating need be used. Thus, for example, one surface of abrick may have a coating of 5 or 10 mills; while others can have thickeror thinner coatings. This will be especially true when the coatings areapplied manually. Uniform coatings are, however, preferred.

The present method is more particularly described in the followingexamples which are intended as illustrative only, since numerousmodifications and variations thereof will be apparent to those skilledin the art.

EXAMPLE I A mixture of rutile titanium oxide ore and coke was clorinatedin a refractory lined cylindrical fiuid bed chlorination vessel. Theshell of the vessel was lined with several courses of refractory brick.Portions of each of three types of refractory brick contained in therefractory lining were treated in the manner hereinafter described withpigmentary titanium dioxide. Table I lists the approximate compositionof the three types of brick treated in this example. The ultimateparticle size of the pigmentary titanium dioxide wa between about .2 andabout .3 micron. Each hidden face of test refractory brick was manuallycoated with the pigmentary titanium dioxide and the excess brushed off.After the bricks in each row were in place, the brick assembly wasgroutetl with the pigmentary titanium dioxide, i.e., each of the exposedjoints between the brick was filled with the pigmentary titaniumdioxide. Then, the remaining exposed face of each inner row of treatedbrick was coated with about a inch layer of the pigmentary titaniumdioxide. The brick surface exposed to the interior of the chlorinationvessel was not treated with the pigmentary titanium dioxide; however,the joints between the bricks were grouted.

After operating the chlorinator at an operating temperature of about1800" F. for about 29 days, the chlorinator was shut down and therefractory brick lining was examined. Various segments of untreatedbrick were found to be about 30 percent corroded and were replaced.After 48 days of total operation, the chlorinator was shut down for ascheduled inspection. The refractory brick lining was again examined andthe refractory brick treated with the pigmentary titanium dioxide werefound to be substantially unaffected by corrosion.

TABLE I Compound Brick A Brick B Brick C 45. l 46. 5 42. 5-45. 0 51. 948. 7 51. 0-53. 5 1. 4 1.8 1.0-2.0 1.7 2. 3 1. 5-2. 5 0. 1 0.2 0. 2-0. 8g0 Trace 0.2 0. 1-0. 6 Alkalles 0.3 0. 0B 0. 5-1. 0

9 EXAMPLE II Following the scheduled shutdown of the chlorinator ofExample I, eroded refractory brick was replaced and treated withpigmentary titanium dioxide in accordance with the procedures of ExampleI. The chlorinator was operated continuously for 60 days until ascheduled shutdown. Inspection of the refractory lining showed thattreated refractory brick suffered little or no deterioration, whileuntreated brick was substantially eroded.

Examples I and II show that treatment of a dry assembly of refractorybrick with refractory metal oxide, e.g., finely-divided titaniumdioxide, prolongs the life of the refractory brick and permits theoperation of the process (chlorination) in the vessel containing thetreated refractory for extended periods of continuous operation untilscheduled shutdowns.

EXAMPLE III Refractory brick in the working section of the chlorinatorof Example I are treated with finely-divided aluminum oxide (A1 in themanner described in Example I. Other sections of refractory brick in thedisengaging section of the chlorinator are treated with pigmentarytitanium dioxide in the manner described in Example I. The chlorinatoris then operated continuously until a scheduled shutdown. Refractorybrick treated with the aluminum oxide and titanium dioxide are theninspected and show little or no deterioration in comparison withuntreated refractory brick cemented together with bonding mortar.

EXAMPLE IV The chlorinator of Example III is operated with zircontreated refractory brick in the working section (instead of aluminumoxide treated brick) and pigmentary titanium dioxide treated brick inthe disengaging section until a scheduled shutdown. Results similar tothat of Example III are observed.

While there are above described a number of specific embodiments of thepresent invention, it is obviously possible to produce other embodimentsand various equivalent modifications thereof without departing from thespirit of the invention.

Having set forth the general nature and specific embodiments of thepresent invention, what is claimed is set forth in the appended claims.

1. A fluidized solid reactor having a refractory brick lining of brickshaving pores or voids present in the surfaces thereof wherein jointsbetween individual bricks of said lining are grouted with materialconsisting essentially of substantially dry, finely-divided, freeflowing refractory metal oxide powder having a melting point greaterthat the operating temperature of the reactor and containing particlespredominately of a size sufliciently small to fill the pores or voidspresent in the surfaces of the bricks, the exposed faces of saidgrouting consisting essentially of said refractory metal oxide powder.

2. A fluidized solids reactor according to claim 1 wherein therefractory brick lining is confined by a metallic shell and the spacebetween the shell and refractory lining is filled with said refractorymetal oxide powder.

3. A fluidized solids reactor according to claim 1 10 whereinsubstantially all of the exposed surface pores in the hidden faces ofsaid brick are filled with finely-divided refractory metal oxide powder.

4. A chlorination vessel having a metal outer shell and an inner liningof at least one layer of refractory brick having pores or voids presentin the surfaces thereof wherein interstices between individual bricks ofsaid lining are grouted with material consisting essentially ofsubstantially dry, finely-divided, free flowing refractory metal oxidepowder having a melting point greater than the operating temperature ofthe chlorination vessel and containing particles predominately of a sizesufficiently small to fill the pores or voids present in the surfaces ofthe bricks, the exposed faces of said grouting consisting essentially ofsaid refractory metal oxide powder.

5. The chlorination vessel of claim 4 wherein the hidden faces of saidrefractory briok contain a superficial coating of said finely-dividedrefractory metal oxide.

6. The chlorination vessel of claim 4 wherein refractory metal oxidethat is resistant to the oxidizing atmosphere within the vessel is usedin the working section of the vessel and refractory metal oxide that isresistant to the reducing atmosphere within the vessel is used in thedisengaging section of the vessel.

7. The chlorination vessel of claim 4 wherein the refractory metal oxideis selected from the group consisting of the oxides of silicon,titanium, zirconium, magnesium, aluminum and mixtures of such metaloxides.

8. The chlorination vessel of claim 4 wherein the refractory metal oxideis pigmentary titanium dioxide.

9. In a fluid bed chlorination vessel having a steel shell andrefractory brick lining, the improvement wherein the lining consistsessentially of a dry assembly of refractory bricks having pores or voidsin the surfaces thereof, the joints between adjacent bricks thereof andexposed pores in hidden brick faces being grouted with substantiallydry, finely-divided, free flowing refractory metal oxide having amelting point greater than the operating temperature of the chlorinationvessel and containing particles predominately of a size suflicientlysmall to fill the pores or voids present in the surfaces of the bricks,the exposed forces of said grouting consisting essentially of saidrefractory metal oxide powder.

10. The chlorination vessel of claim 9 wherein the refractory metaloxide is pigmentary titanium dioxide.

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